1. Field of the Invention
The invention relates to a spacer for a thermal plate in semiconductor process, and more particularly, to a spacer for a thermal plate in a cooling system in semiconductor process.
2. Description of the Prior Art
In the semiconductor processing, the application of the thermal treatment step is very common. A thermal processing recipe typically includes a step of heating a product wafer to a specified temperature for a specified time period for achieving specified result. The heated product wafer is then discharged to a cooling system to reduce the wafer temperature before next process.
The cooling systems conventionally including a cooling arm supplies ambient water as a process cooling medium, and the cooling arm essentially includes a spacer for positioning the product wafer to be cooled down. However, it is found that strong vacuum is often generated in between the product wafer and the spacer during cooling down. Therefore the product wafer is held tightly or stuck up to the spacer, and thus the product wafer suffers scraping, cracking, or even being broken due to different heat expansion coefficients between the product wafer and the spacer.
Therefore, a solution for preventing the wafer to be cooled from being scraped, cracked, or even broken during cooling down is always in need.